BTW ~ I think that the US version of the Hyper 8.5 is coming with 'standard' diffs, not spiders or torsen... Just like the US Hyper 8s did...
Oh, and I am biased with this recommendation. I own a Hyper 8 that has 95% of the upgrades that come with the 8.5 (I have Jammin' FTE big bores instead of the new HoBao BBs). I've raced it quite a bit. Never has there been an instance where I've said to myself that I need to sell mine and get buggy 'x' because its obviously better/faster...
Maybe this helps you.